Dynamical facilitation decreases when approaching the granular glass transition
SPEC, CEA-Saclay, URA 2464 CNRS - F-91191 Gif-sur-Yvette, France, EU
2 Institut de Physique Théorique, CEA, IPhT - F-91191 Gif-sur-Yvette, France, EU
3 CNRS, URA 2306 - F-91191 Gif-sur-Yvette, France, EU
Accepted: 6 October 2010
We investigate the relaxation dynamics of a dense monolayer of bidisperse beads by analyzing the experimental data previously obtained in a fluidized bed. We demonstrate that dynamical facilitation becomes less conserved and plays a lesser role for the structural relaxation when approaching the glass transition. We first show that the dynamics obeys the same elementary processes as those previously reported in a cyclic shear experiment: cage jumps aggregate on a very short time into clusters. We then show that increasing the packing fraction makes the spatio-temporal organization of these clusters evolve from a rather scattered and random distribution towards a collection of sparse and finite avalanche events.
PACS: 45.70.Mg – Granular flow: mixing, segregation and stratification / 45.70.Ht – Avalanches / 61.43.-j – Disordered solids
© EPLA, 2010